Prepared by Jean Paré, P. Eng. Chemco Inc.

Transcription

1 Tools and Methods to Reduce and Control Uncertainties Associated with the Use of In Situ Remediation Techniques (Chemical Oxidation) for Organic Contaminants in Soil and Groundwater Remtech 2010 Banff, Alberta Prepared by Jean Paré, P. Eng. Chemco Inc.

2 The Chemistry works but the geology screw it up Remtech 2010 Banff, Alberta Prepared by Jean Paré, P. Eng. Chemco Inc.

3 Presentation Agenda Chemical Oxidation Technology Review and Limitations Field application challenges and contact issue Tools, testing and tricks Before you get to the field When you re in the field Follow up After injection events Case Study Presentation

4 Chemical Oxidation Technology Review Oxidants are introduced or mixed into the soil and groundwater to attack the organic contaminants Chemical oxidation treatments are commonly used in potable and wastewater applications Oxidants are non-specific and will react with the targeted contaminants AND with the soil organic content (SOD). Chemical oxidation reactions involve the transfer of electrons and the breaking of chemical bonds Water is the carrier for the oxidants used in chemical oxidation (except for ozone) If you have enough oxidant present and sufficient time you will push reaction to FULL mineralization (CO2, H2O, Cl-) of the contaminant of concern

5 Chemical Oxidation Technology Review (2) Common Chemical Oxidants Potassium or sodium permanganate Hydrogen Peroxide alone Catalyzed Hydrogen Peroxide Hydrogen Peroxide with iron (regular Fenton reagent reaction) Need to establish acidic conditions (ideal ph between 4 and 6) Modified Fenton Reagent with chelated species (neutral ph) Ozone Ozone is a gas and must be produced on site The gas must be injected into the soil Persulfate Requires activation to generate free sulphate radicals. Heat, chelated metal, high ph or hydrogen peroxide can be used to activate the persulphate. Activation method can be adapted to site conditions. Percarbonate Requires activation to generate free radicals

6 Chemical Oxidation Limitations All chemical oxidation reactions occur in the WATER or moisture phase (except for ozone) Kinetics of the chemical oxidation reaction is thus influence by the contaminant of concern solubility and availability in the groundwater or moisture phase Sorbed phase contamination might be challenging to remediate (less available) In NAPL containing sites, contamination can persist because of the highly hydrophobic properties of the chemicals that make up the NAPLs Injection technique must induce proper contact between the contaminant and the oxidant for a proper duration for the required reaction to occurs (kinetics)

7 Field application challenges and contact issue Good treatment require good contact Application challenges Geology (Silts and Clays, Sands, gravel and other) Heterogeneity Low GW Velocity < Fracture Pressures High Volumes to inject Reagent Kinetics Depth - Shallow environment - Deep environment

8 Field application challenges and contact issue 14 Subsurface Compartments Potentially Containing Chlorinated Solvents DNAPL Aqueous Sorbed Transmissive Low Pressure Injection Low Pressure Injection Low Pressure Injection Source Low Permeability Mixing or Heating Fracturing Fracturing Transmissive Absent Low Pressure Injection Low Pressure Injection Plume Low Permeability Absent High Pressure Injection High Pressure Injection Vapor x x x x Source Management of Chlorinated Solvents in Soils and Groundwater, August ESTCP

9 Tools, testing and tricks Before you get to the field Validating the qualification and quantification of the selected oxidant or amendment with bench scale lab study Soil and Groundwater Oxidant Demand validation and treatability study are ALWAYS recommended (If it doesn t work in the lab in ideal contact condition it WON T work in the field) Make sure you have all the necessary data and you injection plan is set properly

10 Tools, testing and tricks Carus Haz Rem Assessment Process Preliminary Site Assessment Before Aquifer you Characteristics get to the Geology field Permeability Hydraulic conductivity Heterogeneity Contaminant phase Contaminant Distribution Determine delivery method Soil Geochemistry Porosity Particle size distribution Soil moisture Fe ph TOC Determine the number and location of oxidant delivery point Groundwater Geochemistry ph Alkalinity DO COD TOC Fe +2 and Mn +2 Metals Pilot-scale testing And modeling Determine oxidant Loading rates Additional Site Characterization (if necessary) Contaminants of Concern (COCs) Treatability Study Soil oxidant demand Groundwater oxidant demand Contaminant oxidant demand Degradation kinetics Determine estimated remediation duration (Adapted from R. L. Siegrist et al., Principles and Practices of In Situ Chemical Oxidation Using Permanganate, p. 202.)

11 Tools, testing and tricks Search and Destroy Methodology Targeted Distribution Data Gap Analysis High Resolution Characterizati on 3D Graphing & Conceptual Model Technology Selection High Resolution Remediation Design Distribution Testing Optimized Full Scale Application Troubleshooti ng Source - Vironex 11

12 Tools, testing and tricks When you re in the field Making sure you are injecting in the adequate zone CHARACTERIZE, CHARACTERIZE, CHARATERIZE Validating the distribution and dilution of the oxidant or amendment in the subsurface aquifer through the use of an INERT tracer PRIOR moving with you re expensive oxidant or amendment. Evaluate the pro and cons of the various equipments and techniques to induce proper contact

13 Tools, testing and tricks Search and Destroy Methodology Targeted Distribution Data Gap Analysis High Resolution Characterizati on 3D Graphing & Conceptual Model Technology Selection High Resolution Remediation Design Distribution Testing Optimized Full Scale Application Troubleshooti ng Source - Vironex 13

14 Search - How The MIP Works Nitrogen Carrier Gas Permeable Membrane Heater Block C Soil Conductivity Source - Vironex

15

16 Search - How The HPT Works The HPT uses a sensitive, down hole transducer to measure the pressure response of the soil to injection of water. Identify hydraulic conductivity of zones for injection identified by the MIP not provided by the EC Measures static water conditions across a site. Source - Vironex

17 Search - Why MIP/HPT before injecting? Locate contaminant mass through high vertical resolution Define injection flows and pressures Don t get fooled by tight sands or clays with low conductivity

18 Tools, testing and tricks Search and Destroy Methodology Targeted Distribution Data Gap Analysis High Resolution Characterizati on 3D Graphing & Conceptual Model Technology Selection High Resolution Remediation Design Distribution Testing Optimized Full Scale Application Troubleshooti ng Source - Vironex 18

19 MIP 3D Imaging / Injection Locations

20 Radius of Influence (ROI) Pore Volume ROI ROI Reagent Per Location 500 gals Injection Volume as a % of Effective Pore Volume 100% Pore Volume ROI 2 feet Advection / Dispersion ROI + = Additional ROI from Advection / Dispersion (Feet) Time Frame To Achieve Advection / Dispersion ROI (Days) 60 days 9 feet 7 feet 60 Days 4 10 ROI = P ROI + A/D ROI ROI = pore volume ROI (ft) + advection/dispersion ROI (ft) 9 feet = 2 feet days Kinetics > ROI T

21 ROI Realities Pore Volume ROI ROI Reagent Per Location 500 gals Injection Volume as a % of Effective Pore Volume 50% Pore Volume ROI 2 feet Advection / Dispersion ROI Additional ROI from Advection / Dispersion (Feet) Time Frame To Achieve Advection / Dispersion ROI (Days) 60 days 9 feet 7 feet 60 Days Tight Soils Low Injection Pore Volumes Tighter Spacing Higher Reagent Concentrations Permeable Soils / Flat Gradient Reagent Persistence Requires High Injection Pore Volume Exceed Fracture Pressure Stay Below Fracture Pressure Permeable Soils / Steep Gradient Lower Residence Time

22 Distribution Primarily Advection Driven 10 30% pore Volume Advection & Dispersion Advection Only

23 Injection < Fracture Pressure P Imax < [(d dry g h dry + d sat g h sat ) d water gh sat ] psi P Imax = Maximum injection pressure to prevent structural failure (fracturing) Rule Of Thumb----- P Imax = DPT p +(DTI * 0.5PSI) (includes safety factor) DTI = Depth To Target Interval DPT p = Direct Push Compaction Factor Source: Remediation Hydraulics Payne, Quinnan, Potter - CRC Press

24 Tools, testing and tricks Search and Destroy Methodology Targeted Distribution Data Gap Analysis High Resolution Characterizati on 3D Graphing & Conceptual Model Technology Selection High Resolution Remediation Design Distribution Testing Optimized Full Scale Application Troubleshooti ng ROI Injection Volumes Source - Vironex Pressure Delivery Tooling

25 Delivery Systems Source - Vironex Direct Push Bottom Up or Top Down Low to Moderate tools (screens 1 to 5 feet) targeting of discrete lithologies Injection Wells Injection wells Packer isolation of open bore holes Fracturing DPT fracturing of tight formations Pneumatic and Hydraulic Extraction / Injection Electrokinetic Injection Pressure Low Low to High Moderate to High Low

26 Destroy - Why Distribution Testing Avoid Major Design Changes During Full Scale Confirm Injection Pressure and Flow Assumptions Confirm Formation Acceptance of Design Volume Confirm Vertical and Horizontal Distribution of Reagents Over Time Source - Vironex

27 Tools, testing and tricks Follow up After injection events Validate oxidant/amendment distribution (may integrate inert tracer to evaluate dilution factor) with : Core samples Hydropunch sampling Electrical Conductivity Groundwater sampling through monitoring well

28 Outputs Visual Data Dry Cleaner Case Study Injection Strategic Injection Strategy Source: Vironex

29 Outputs Visual Data MIP Post Injection Injection Pre Injection MIP Strategic Injection Strategy Post Injection MIP Source: Vironex

30 Who we are Canadian Company founded in 1988 Production and warehouse facilities in Quebec, Ontario and in Western Canada with Quadra Chemicals Sectors of activity - Industrial and Municipal Waste Water - Contaminated Soil and Groundwater - Air, Odours and Atmospheric Emissions - Process Water Products: coagulants, flocculants, nutrients, bacterial preparations strains, oxidants, catalysts, oxygen and hydrogen release compounds, odour control agents Services: technical support, product selection, product supply and sourcing, logistics, laboratories (SOD and treatability testing), design and staff training.

31 Acknowledgements Carus Chemical FMC Corporation Progressive Engineering & Construction Vironex Thank you for your attention! Have a good day!!! Contact information: Chemco Quadra Chemicals jean.pare@chemco-inc.com Henry_wu@quadrachemicals.com Tel: (604) Web site: